<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>样式演示</title>
    <style>

        div {
            border: 1px solid red;
        }

        .top {
           text-align: center;
            background: bisque;
        }
        .navibar{
            text-align: center;
            background: deeppink;
        }

        .left {
            width: 20%;
            float: left;
            height: 500px;
            background: bisque;
        }

        .center {
            width: 59%;
            float: left;
            height: 500px;
            background: chartreuse;
        }

        .right {
            width: 20%;
            float: left;
            height: 500px;
            background: darkorange;
        }

        .footer {
            /*清除浮动*/
            clear: both;
            background: gray;
            text-align: center;
        }

    </style>
</head>
<body>

<div class="top" >top</div>
<div class="navibar">
    <a href="" >登录</a>&nbsp;&nbsp;
    <a href="">注册</a>
</div>
<div class="left">left</div>
<div class="center">center</div>
<div class="right">right</div>
<div class="footer">footer</div>
</body>
</html>